数据结构案例学习-二分法数组找元素位置

代码如下

# include <stdio.h>

int main(void)
{
	int left = 0, right = 80, n = 0;
	int mid, i, num = 30;
	int a[81];   //定义数组大小

	mid = (left + right)/2;//定义中间比较值的下标
	
	for(i = 0; i <= 80; i++)//数组元素顺序赋值
	{
		a[i] = i;	}

	while(num != a[mid] )//循环直到与比较值相等
	{
		mid = (left + right)/2;
		n++;		//比较次数
		if(a[mid] == num)
		{
			break;		}
		else if (a[mid] < num)//值在左边区间
		{
			left = mid++;	}
		else
		{
			right = mid--;	}
	}
	printf("%d, num = %d\n",n,a[mid]);
	return 0;
}